Journal of the International Neuropsychological Society

Table of Contents - 2007 - Volume 13, Issue 03  


NEUROBEHAVIORAL GRAND ROUNDS

Intrahemispheric reorganization of language in children with medically intractable epilepsy of the left hemisphere

DARREN S.  KADIS  a1 a2 , KOJI  IIDA  a3 , ELIZABETH N.  KERR  a2 , WILLIAM J.  LOGAN  a4 a5 , MARY PAT  MCANDREWS  a1 a6 , AYAKO  OCHI  a5 , HIROSHI  OTSUBO  a4 a5 , JAMES T.  RUTKA  a7 , O. CARTER SNEAD  III  a4 a5 , SHELLY K.  WEISS  a4 a5 and MARY LOU  SMITH  a1 a2 c1
a1 Department of Psychology, University of Toronto, Toronto, Ontario, Canada
a2 Department of Psychology, Hospital for Sick Children, Toronto, Ontario, Canada
a3 Division of Neurosurgery, Hiroshima University, Hiroshima, Japan
a4 Department of Pediatrics, Division of Neurology, University of Toronto, Toronto, Ontario, Canada
a5 Department of Neurology, Hospital for Sick Children; Toronto, Ontario, Canada
a6 Applied and Interventional Research, Toronto Western Research Institute, Toronto, Ontario, Canada
a7 Department of Surgery, Division of Neurosurgery, University of Toronto, and Department of Neurosurgery, Hospital for Sick Children, Toronto, Ontario, Canada

Article author query
kadis ds   [PubMed][Google Scholar] 
iida k   [PubMed][Google Scholar] 
kerr en   [PubMed][Google Scholar] 
logan wj   [PubMed][Google Scholar] 
mcandrews mp   [PubMed][Google Scholar] 
ochi a   [PubMed][Google Scholar] 
otsubo h   [PubMed][Google Scholar] 
rutka jt   [PubMed][Google Scholar] 
iii ocs   [PubMed][Google Scholar] 
weiss sk   [PubMed][Google Scholar] 
smith ml   [PubMed][Google Scholar] 

Abstract

We investigated language representation in nine children (six male, three female; 5.6–17.7 years of age) who underwent surgical treatment of medically intractable epilepsy of the left hemisphere. Although interhemispheric reorganization has been previously documented in similar groups, this is the first study to systematically evaluate possible intrahemispheric effects of early insult. All cases had left hemisphere seizure foci and underwent extraoperative stimulation mapping (ESM) for language localization prior to receiving cortical resections. To compare ESM findings across subjects and to assess intrahemispheric reorganization, we developed a novel coregistration technique whereby independent raters plotted two-dimensional (2D) ESM findings in 3D standard space. Expressive language sites identified with ESM were compared with a structural probability map of pars opercularis, or Broca's area. The average difference between independent raters' estimates of 28 language sites was 3.9 mm (SD = 2.0), indicating excellent agreement; the coregistration procedure permitted assessment of 2D ESM findings in 3D standard space. We observed language sites in regions substantially anterior and superior to canonical Broca's area, possibly reflecting intrahemispheric reorganization. Findings suggest that left hemisphere insult in young children may result in anterior displacement of language within the frontal cortex. (JINS, 2007, 13, 505–516.) a

(Received March 8 2006)
(Revised September 21 2006)
(Accepted September 21 2006)


Key Words: Pediatric; Plasticity; Extraoperative stimulation mapping; Subdural electrodes; Coregistration; Brain mapping.

Correspondence:
c1 Correspondence and reprint requests to: Dr. Mary Lou Smith, Department of Psychology, University of Toronto at Mississauga, 3359 Mississauga Road North, Mississauga, Ontario L5L 1C6, Canada. E-mail: smithml@psych.utoronto.ca

Footnotes

a This study was drawn from a thesis submitted by D.S.K. in partial fulfillment of requirements of the MA degree through the Graduate Program in Psychology and the Collaborative Program in Neuroscience at the University of Toronto (Ontario, Canada).


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